/**
* This file is part of ORB-SLAM2.
*
* Copyright (C) 2014-2016 Raúl Mur-Artal <raulmur at unizar dot es> (University of Zaragoza)
* For more information see <https://github.com/raulmur/ORB_SLAM2>
*
* ORB-SLAM2 is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* ORB-SLAM2 is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef YGZ_LOOPCLOSING_H_
#define YGZ_LOOPCLOSING_H_

#include "Common.h"
#include "ORBVocabulary.h"
#include "IMU/configparam.h"

// Loop closing 线程
// 基本没动，除了加IMU部分

namespace ygz {

    class Tracking;

    class LocalMapping;

    class KeyFrameDatabase;

    class KeyFrame;

    class Map;

    class MapPoint;

    class LoopClosing {
    public:
        EIGEN_MAKE_ALIGNED_OPERATOR_NEW
        typedef pair<set<KeyFrame *>, int> ConsistentGroup;
        typedef map<KeyFrame *, g2o::Sim3, std::less<KeyFrame *>,
                Eigen::aligned_allocator<std::pair<const KeyFrame *, g2o::Sim3> > > KeyFrameAndPose;

        LoopClosing(Map *pMap, KeyFrameDatabase *pDB, ORBVocabulary *pVoc, const bool bFixScale, ConfigParam *pParams);

        void SetTracker(Tracking *pTracker);

        void SetLocalMapper(LocalMapping *pLocalMapper);

        // Main function
        void Run();

        void InsertKeyFrame(KeyFrame *pKF);

        void RequestReset();

        // This function will run in a separate thread
        void RunGlobalBundleAdjustment(unsigned long nLoopKF);

        bool isRunningGBA() {
            unique_lock<std::mutex> lock(mMutexGBA);
            return mbRunningGBA;
        }

        bool isFinishedGBA() {
            unique_lock<std::mutex> lock(mMutexGBA);
            return mbFinishedGBA;
        }

        void RequestFinish();

        bool isFinished();

        ConfigParam *mpParams;
        bool mbUseIMU;

        bool GetMapUpdateFlagForTracking();

        void SetMapUpdateFlagInTracking(bool bflag);

    protected:

        bool CheckNewKeyFrames();

        bool DetectLoop();

        bool ComputeSim3();

        void SearchAndFuse(const KeyFrameAndPose &CorrectedPosesMap);

        void CorrectLoop();

        void ResetIfRequested();

        bool mbResetRequested;
        std::mutex mMutexReset;

        bool CheckFinish();

        void SetFinish();

        bool mbFinishRequested;
        bool mbFinished;
        std::mutex mMutexFinish;

        Map *mpMap;
        Tracking *mpTracker;

        KeyFrameDatabase *mpKeyFrameDB;
        ORBVocabulary *mpORBVocabulary;

        LocalMapping *mpLocalMapper;

        std::list<KeyFrame *> mlpLoopKeyFrameQueue;

        std::mutex mMutexLoopQueue;

        // Loop detector parameters
        float mnCovisibilityConsistencyTh;

        // Loop detector variables
        KeyFrame *mpCurrentKF;
        KeyFrame *mpMatchedKF;
        std::vector<ConsistentGroup> mvConsistentGroups;
        std::vector<KeyFrame *> mvpEnoughConsistentCandidates;
        std::vector<KeyFrame *> mvpCurrentConnectedKFs;
        std::vector<MapPoint *> mvpCurrentMatchedPoints;
        std::vector<MapPoint *> mvpLoopMapPoints;
        cv::Mat mScw;
        g2o::Sim3 mg2oScw;

        long unsigned int mLastLoopKFid;

        // Variables related to Global Bundle Adjustment
        bool mbRunningGBA = false;
        bool mbFinishedGBA = true;
        bool mbStopGBA = false;
        std::mutex mMutexGBA;
        std::thread *mpThreadGBA;

        // Fix scale in the stereo/RGB-D case
        bool mbFixScale;
        bool mnFullBAIdx;

        std::mutex mMutexMapUpdateFlag;
        bool mbMapUpdateFlagForTracking = false;
    };

} //namespace ygz

#endif // LOOPCLOSING_H
